Any Good or ??

Lyndon302 · 02:53 PM

Pistons alone are 1300 USD if I buy them
I have a 67S and looking refresh the pistons and barrels. I currently have 80.5 mm std Porsche S pistons. First over size and no rings available anywhere.
I take it these are Chinese Barrels. My main concern is deck height and shimming. I had an issue with Wiseco pistons and now I'm gun shy.
Lyndon
https://aapistons.com/products/porsche-81mm-je-forged-piston-and-cylinder-kit

Lyndon302 · 01-07-2021, 02:53 PM

Bump

Eagledriver · 01-07-2021, 04:54 PM

I would buy those in a heartbeat. I don’t think you can buy Chinese biral cylinders. These are probably Mahle cylinders with JE pistons. Buy them and measure the clearance. Should be a great solution to your cylinder problem.

-Andy

Lyndon302 · 01-07-2021, 04:55 PM

That would be to good to be true
Lyndon

targa72e · 01-08-2021, 11:27 AM

Actually I don't think that is the case. I don't think Mahle offers the biral cylinders anymore. All the new 2.2/2.4 Mahle piston and cylinder sets I have seen use nickasil aluminum cylinders like all the later models.

There current Porsche catalog does not show different cylinders for early cars.

http://www.us.mahle.com/media/usa/motorsports/2020porscheapguideforapproval.pdf

If you search for new P&C sets for these early cars they will mostly be listed as nickasil unless they are old stock.

If you search AA cylinders I believe there are a couple threads that discuss them. From what I remember they had issues on meeting dimensional specs. One solution I remember was to buy the cylinders and then send them off to be bored and plated to get in tolerance cylinder sets.

john

Eagledriver · 01-08-2021, 05:52 PM

Looks like they are in the LA area. I’d give them a call to see what the source of the cylinders is. I assumed that they were reconditioned Mahle cylinders, but maybe not?

-Andy

Henry Schmidt · Henry Schmidt's Garage

The AA cylinders are new construction Biral barrels.
We've used them for years. The price point is hard to beat.
The issues we found were indeed, specs and cast iron hardness. Although Rockwell is not used on cast iron, we measured the hardness to be 25% softer than stock Mahle Birals. (Caveat: Mahle cylinders we tested were used and perhaps heat cycled to create a harder surface?)
Many of the cylinders we tested were oversized which made piston clearance and ring gaps unexceptionable.
Our solution was to send the new AA cylinder to Millennium to have them bored true and Nikasil coated. This requires a different ring pack so we order custom pistons with appropriate ring pack to match the new coated cylinders.
Taking a used set of out of spec Mahle 84 mm cylinders and having them coated is a great option as well. It leaves the external appearance of the engine more correct.